Radio receiving system



Dec. 22, 1931. A. RlSTOW RADIO RECEIVING SYSTEI Filed Feb. 27, 192

2 Sheets-Sheet 2 Ely-'1 Jlfarney Patented Dec. 22, 1931 I I i UNITEDSTATES PATENT OFFICE ALFRED RIS TOW, OF BERLIN-NEW COLOGNE, GERMANYRADIO RECEIVING SYSTEM Application filed February 27, 1928, Serial No.257,224, and in Germany February 22, 1927.

An application was filed in Germany, Febof example, in combined Figures1 and 1a ruary 22, 1927. of the accompanying drawings, while Figure Thepresent invention relates to radio re- 2 shows a feature appearing inFigure 1 ceiving systems in which the point at which more in detail v 5reception actually occurs is remote from the The arrangement depictedcomprises two apparatus aiiected by the aerial radiations, receivingapparatus 151- and E2 with a It has been found that owing to well-knownsingleknoh control constructed in such a causes of various kinds, it isimpossible to manner that by turning the tuning knob install receivinginstallations which should from the zero mark on the scale the aerial 10be capable at any 'momentof receivingmesand the heating circuit areswitched in. It

sages in cities. Examples of such installawill be shown later on that,one receiver can tions are subscribers toa press service, stock be,worked only after the other one has been exchange service orweatherservice and reswitched oil. The telephone leads T1 and ceivinginstallations of public authorities; 'T2are connected to the winding VVlof the All these installations mustbe capable at any ring repeater U1,the secondary windingof moment of receiving in a reliable manner theWhich is tapped in the centre, whilst to the messages intended for them,as on the one outer ends the transmission lines L1, L2 are handdependence isplaced on them and on connected and lead tothe tappedwinding the other hand such messages are mostly sent W3 of the ringrepeater U2, the secondary 0 only once. In order to ensure adequaterewinding of which contains a telephone T or ception, such receivinginnallat-ions must be other signal r produci g apparatus. located out oftowns, the reception room in F or eflecting the remote control, two thetown being connected to the receiving three-pole control keys S251 andSt2 are proinstallation by means of a telephone line. vidcd. Thenegative pole of the battery B1 The drawback of this arrangement is thatis connected to the contacts a of the two it is necessary to have aspecial stafi for the keys, the contacts 0 to the positive pole,receiving apparatus who have nothing to do whilst the contact I) of thekey St2 is con but to tune it, whilst the messages are renected toearth'and the contact I) of the key ceived by the staff in the town. Thecondi- Stl to the tapping of the winding V3, with tions are similar inall cases in which the the interposition of a milliammeter MA.transmitting and receiving installation is .to When the key stl. isdepressed, the positive be worked from a central station. In order poleof the battery will be connected'to the to avoid disturbance by thetransmitter, it is line and the negative pole to earth, but whennecessary to arrange the receiving installathe key 852 is depressed, thepositive pole tion separately and spaced from the" transwill beconnected to earth and the negative 35 mitter or from the centralworking station. pole to the line. By depressing the two According tothe invention, these drawkeys as desired it is therefore possible tobacks are avoided by a remote electrical consend currents into thetransmission line in -trol of the receiving apparatus which is efeitherdirection.

fected by means of the transmission line. In The tapping of the windingW2 of the order to guarantee reliability of reception ring repeater U1isconnected to earth with even in the event of a valve burning out, twothe interposition of a resistance R and of a or more receiving apparatuswhich can be two-polerelay MR so that, bythis circuit, the

- switched in and out at will by means ofthe control circuit is closedthrough the earth.

said remote control are provided. The cost At the same time the circuitis also closed of the second receiving apparatus is compenthrough theresistance R and through the sated for many times by economy in theatrelay Rt to earth. According to the directendant stafl. tion of thecontrol current, the relay MR One way of carrying the invention intowill be thrown over in'one direction or the effect is diagrammaticallyillustrated by way otherand in that way a series motor HM,

which effects the tuning of the receivers, is correspondingly connectedto the battery 132 and its direction of rotation determined accordingly.

The mechanical arrangement will be explained first for the receiverE2:-The tuning knob K of the receiver E2 is connected, with theinterposition of various gear wheels, to the movable part of a clutchmagnet TM2, to which current is supplied through two slip rings 1 and 2.The driving spindle of the clutch magnet engages, by means of anothergear wheel, with the gear wheel Z which is mounted on the same spindleas the resistance R and the operating wheel Sch of a three-pole switchDR driven by the series motor HM with the interposition of worm wheelsor other gearing. The resistance R comprises an annular winding which isrigidly secured to the spindle, whilst current is supplied through theslip ring 3 and the brush l.

The three-pole switch DH is shown in detail in Figure 2. On theoperating wheel Sch two stops or tappets are mounted one at each sideand suitably displaced relatively to each other. When the operatingwheel is turned clockwise, as assumed by way of example in the drawings,the lever H1 of the three-pole switch will be rocked and brought intothe position shown in dotted lines until it engages with a spring F1mounted on a magnet, the winding of which is always eX- cited. Theconstruction in the present ex ample is such that the spring ismagnetized and is in a position to hold the lever H1 in the dottedposition, but some other arrangement, say with a permanent magnet, couldalso be employed. When the operating wheel continues to move in thedirection. indicated, the spring will be compressed until the stop a1slides off the lever H1, when the spring will return to its position ofrest. but will still hold the lever H1, fast magnetically. The currentsupply points are the centres of rotation of the lever, and the springF1. The result of the magnetic retention is that the circuit will not bebroken in spite of the operating wheel continuing to rotate, but if thedirection of rotation is reversed, the lever H1 will be detached fromthe spring only at the moment when the stop c1 touches the lever H1, andthe contact will be interrupted. The setting of the operating wheelmustbe such that at the beginning of the contact closing, the clutchmagnet TM2 and therefore the tuning device of the receiver which at thismoment should be at zero. will be switched on. A rotation of 180 on thetuning scale may correspond for instance to a rotation of 200 of theoperating wheel; by a rotation of 200 the whole range of tuning of thereceiver E2 will therefore have been traversed. If the operating wheelSch is turned baclm'ards, then at the moment when the marking 0 on thetuning scale is reached, the contact by the lever H1 will be broken andthe receiver E2 switched off. If the operating wheel continues to rotatein the same direction (that is to say in the direction opposite to thatassumed in the drawings), after a short time the stop a2 indicated atthe other side of the wheel will strike the lever H2, and therefore theclutch magnet TMl of the receiver E1 will be switched in. The same thingis repeated as before, with the difference that an increase in thetuning scale reading corresponds to anti-clockwise rotation of theoperating wheel and vice versa. This can be easily obtained by a correctarrangement of the transmission gear. In Figure 1 the three-pole switchis shown somewhat differently for the sake of clearness. lVhen the relayMR is thrown over in the manner above described by depressing a key 55/1or @2 2 the motor ill i will rotate in a corresponding direction. At thesame time the wheel Sch of the three-pole switch will start and close bymeans of the lever H1 the following circuit t-negativc pole of thebattery B2, contact of the relay R25 the relay acts at the moment whenthe relay MR is thrown over), centre of rotation of H2, contact springF1, slip ring 1, clutch magnet TM2, slip ring 2, positive pole of thebattery.

The motor will continue to rotate until the depressed key is releasedbut when the circuit is broken the relay MR will return to the positionof rest and the relay Rt will fall off and break the circuit of theclutch magnet. The latter will instantaneously release, whilst the motorhas time to run down slowly; if the clutch magnet and the relay Rt werenot provided the tuning would be lost again owing to the running down ofthe motor.

If it is desired to pass from the receiver E2 to the receiver E1, firstthe tuning of the receiver E2 is brought to Zero and then the re--ceiver E1 is tuned in a similar manner.

It is obvious that the tuning could be effected simultaneously with thelistening, and that it is possible to go back with the tuning at willeven if the range has been passed.

As the resistance R is rigidly secured by a common spindle to theoperating wheel of the three-pole switch, to each position of the switchthere will correspond a given value of the resistance. As the otherresistance values of the circuit, viz., the repeater coil, line andrelay MR are constant, the milliammeter MA provided in the listeningroom, can be calibrated to the position of the operating wheel of thethree-pole switch and in. that way the tuning of the receivers can beread on the milli ammeter.

l Vhat I claim is:

1. 1'. radio receiving system comprising in combination areceivinnapparatus embodying two receivers and a signal reproducingapparatus located at a distance from said receiving apparatus, atransmission line connecting said receiving and signal reproduc-V ingapparatus, means in proximity to' said signal reproducingapparatus forsending through said transmission line an electric current, control keysin proximity to said signal re roducing apparatus for varyingcombination a receiving apparatus and a sig nal reproducing apparatuslocated at a distance from said recelving apparatus, a transnission lineconnecting said receiving and signal reproducing apparatus, means inproximity to said signal reproducing apparatus for sending through saidtransmission line an electric current in either direction, tuning meansin said receiving apparatus, a motor responsive as regards directionofrotation to said current, an operative connection between said motorand said, tuning means, a clutch in said connection, means whereby saidclutch is engaged on rotation of said motor in one direction, and meansfor retaining said clutch in engagement independently of the continuanceof said rtation.

3. A radio receiving system comprising in combination a receivingapparatus and a signal reproducing apparatus located at a distance fromsaid receiving apparatus, a transmission line connecting said receivingand signal reproducing apparatus, means in proximity to said signalreproducing apparatus for sending through said transmission line anelectric current in either direction, tuning means in said receivingapparatus, a motor responsive as regards direction of rotation to saidcurrent, an operative connection between said motor and said tuningmeans, a clutch in said connection, means whereby said clutch is engagedon rotation of said motor in one direction, means for retaining saidclutch in engagement independently of the continuance of said rotation,and

means for disconnecting said clutch when said current is stopped or onreversal of said rotation.

l. A radio receiving system comprising in combination a receiviapparatus and a sig- D nal reproducing apparatus located at a d1stancefrom said receiving apparatus, a transmission line connecting saidreceiving and signal reproducing apparatus, means in proximity to saidsignal reproducing apparatus for sending through said transmission linean electric current 1n either direction,

tuning means in said receiving apparatus, a motor responsive asregardsrdirection of rotation to said current, an operative connectionbetween said motor and said tuning means, a clutch in said connection,means whereby said clutch is engaged on rotation of said motor in onedirection, and means responsive to the cessation of said current forstopping said motor and for immediately disconnecting said clutchalthough said motor continues rotating during a runningdown period.

5. A radio receiving system comprising transmission line to which saidreceivers and said signal reproducer are connected, tuning means foreach of said receivers, operating mechanism for said tuning means, andremote control means located in proximity to the signal reproducer andcontrolling over said transmission line said operating means forselecting and tuning either receiver.

6. A radio receiving system comprising two receivers, a signalreproducerv located at a point distant from-said receivers, a twowiretransmission line to which said receivers and said signal reproducer areconnected, a tuner for each of the receivers, operating means forv thetuners including a motor rotatable in opposite directions for selectingand tuning therespective receivers, and remote control means located inproximity to the signal reproducer for supplying current of oppositepolarity over said transmission line for controlling the direction ofrotation of the motor.

. 7. A radio receiving system comprising in combination two receivers, asignal reproducer located at a distance from said receivers, atransmission line to which the sig-' nal reproducer is connected,operating means for the tuners of the receivers including a motorrotatable in reverse directions for ac tuating said operating means forselectively tuning the respective receivers, coupling devices forautomatically connecting the motor with the tuner of one or the other ofthe receivers on the rotation of the motor in opposite directions, andmeans for supplying an electric current in either direction through saidline to rotate the motor in one direction or the other.

8. A radio receiving system comprising in combination a receivingapparatus incliiding a tuner and a signal reproducing apparatus locatedat a point distant from said receiving apparatus, a line circuit towhich the reproducing and the receiving apparatus are connected, meansin proximity to said signal reproducing apparatus for transmitting acurrent through said line circuit to control the operation of the tunerof the receiving apparatus, means in proximity to said receivingapparatus responsive to said control 7 two receivers, a signalreproducer located at a i distant polnt from said receivers, a two-wirecurrent for continuously tuning said receiving apparatus between widelydifferent Wave length ranges, a device variable with the setting of saidtuning and located in the path of flow of said control current andoperable to vary said current, and an indicator in proximity to saidsignal reproducing apparatus responsive to said variable current.

9. A radio receiving system comprising in combination a receivingapparatus and a sig nal reproducing apparatus located at a point distantfrom said receiving apparatus, a transmission line connecting saidreceiving and signal reproducing apparatus, means ineluding a pluralityof keys in proximity to said signal reproducing apparatus for connectingto said transmission line currents of opposite polarity, operatingmechanism including a polar relay responsive to said current foractuating the tuning means of said receiving apparatus, an electricalresistance variable with the setting of said tuning means and located inthe path of How of said current, and an indicating instrument responsive to said current in proximity to said signal reproducingapparatus.

10. A radio receiving system comprising a plurality of receivers, asignal reproducer located at a distance from said receivers, a sig naltransmission line extending between the receivers and the signalreproducer, tuning mechanism for each receiver, operating means for thetuning mechanisms, a selector "for selecting the receiver to be tuned,and remote control means located in proximity to the signal reproducerand serving, when actuated, to control over said signal transmissionline the operation of said selector and said operating means.

In testimony whereof I have affixed my signature.

DR. ALFRED RISTOVV.

